Here is a page about John’s Canal, which was used to extract turf from Macnab’s Bog at Mona Lodge, Portcrusha, between Castleconnell and Montpelier in Limerick (Montpelier is at the other end of the bridge at O’Briensbridge).
The bog seems to have been opened by John Brown (or Browne) of the Stein Brown(e) Distillery at Thomondgate in Limerick. Turf was carried by water from the bog to the distillery, where it was used to fuel the first steam engine in Limerick. The bog was managed by James Macnab, who took over the lease in 1841; after his death his son Alexander Allen Macnab took over. The bog was an early operation of a managed industrial extraction and production enterprise, operating throughout most of the year and drying the material to produce “stone turf”. About 5000 tons were produced each year.
The canal system had a wooden bridge (now vanished), several branches (some still visible), a lock gate (gone) and a stone pier/quay (still visible).
Irish waterways history 